1. Field of the Invention
This invention relates generally to construction kits by means of which a do-it-yourself can erect a stable structure, and in particular to a kit of this type whose components can be assembled to create a walled structure whose predetermined geometry is maintained even when the structure is subjected to stresses.
2. Status of Prior Art
A conventional article of furniture such as a cabinet whose components are made of wood, plastic or composite materials, is usually assembled at a factory by means of screws, bolts or other fasteners, or by gluing the joints. Once the cabinet is finished and in condition to be sold, it must be crated and shipped to a retailer. When the retailer sells the cabinet, he must ship it in its finished state to his customer.
The cost of crating and shipping finished articles of furniture may in some instances approach its selling price. And the selling price cannot be low because it must cover the cost of assembling the article.
It is for these reasons that a large share of the furniture market has now been taken over by so-called “knock-down” furniture, such as those sold internationally by the IKEA furniture chain. What the consumer buys is not a finished article of furniture but a kit containing all of its components accompanied by instructions explaining to a do-it-yourself what must be done to assemble the components. Also included in the kit are screws and other fasteners necessary to join the components together as well as the tools for this purpose such as a wrench and screwdriver.
But a do-it-yourself is an amateur, not a professional craftsman, and when assembling a knock-down piece, the resultant structure may be somewhat misshapen and unstable.
One difficulty a do-it-yourself is likely to encounter is when erecting a structure having wall panels that must be mounted on frames. If the frames erected by the do-it-yourself are not quite rectangular, he will find it difficult to attach rectangular panels to these frames. Thus if a frame is provided with holes to receive screws for mounting a panel, and the panel is provided with matching holes, these panel holes will be out of registration with those in the frame should the frame not be perfectly rectangular.
A more troublesome aspect of an article of furniture assembled from a kit of parts is the so-called parallelogram effect. When a regular frame defined by parallel end beams attached to parallel side beams has a panel secured thereto is subjected to stresses, as are most articles of furniture, this may give rise to the parallelogram effect in which the end beams assume an acute angle with respect to the side beams.
To avoid this undesirable effect it is the common practice to reinforce the frame with guy wires extending diagonally in an X-formation from the four corners of the frame to resist its deformation. These guy wires are not only unsightly but they add to the cost of the do-it-yourself article and to some degree defeat its purpose which is to provide the consumer with a kit by which he can assemble an article that will be significantly less expensive than a pre-assembled, factory-made article.